In a variable magnetic flux motor and a variable magnetic flux generator, two types of magnets, a variable magnet and a stationary magnet, are used. Conventionally, in the variable magnet, an Al—Ni—Co based magnet or a Fe—Cr—Co based magnet is used. In order to increase performance and efficiency of the variable magnetic flux motor and the variable magnetic flux generator, improvement in coercive force and magnetic flux density of the variable magnet is demanded. As high-performance permanent magnets, Sm—Co based magnets are known. Among the Sm—Co based magnets, an Sm2Co17 type magnet has a two-phase separation structure of a 2-17 crystal phase and a 1-5 type crystal phase, and obtains magnetic characteristics by a coercive force exhibition mechanism of magnetic domain wall pinning type.
The Sm2Co17 type magnet has excellent coercive force and largest magnetic energy product, but is costly because it contains a large amount of cobalt, and has small magnetic flux density compared to a magnet which is constituted mainly of iron. To improve magnetic flux density of the Sm2Co17 type magnet, it is effective to increase an iron concentration, and the Sm2Co17 type magnet can be reduced in cost by increasing the iron concentration. However, the Sm2Co17 type magnet with a high iron concentration has a tendency of steep rising of initial magnetization curve. For the variable magnet, in order to have a large variable width, a magnet having a small gradient of rising of initial magnetization curve is demanded. Accordingly, in the Sm2Co17 type magnet with a high iron concentration composition, suppression of the rising of initial magnetization curve is demanded.